Storage and shipping of biologically active materials used, for example, in pharmaceutical industry are problematic since these materials are prone to degradation, especially thermal degradation. This is particularly true in case of biologically active materials such as vaccines which can be distributed worldwide and may thus be submitted to different temperatures depending on the countries of distribution or to temperature variation during transport. This further limits distribution of the biological materials to developing nations with limited infrastructure.
Therapeutic activity of virus-based materials, including viruses, viral particles, viral vaccine, requires that their structural integrity is maintained during storage and/or shipping in order to be infectious and/or biologically active.
This structural integrity of a virus-based material is often compromised during the formulation process, thus precluding its therapeutic use. Said therapeutic activity further requires that the viral titer loss, and particularly the infectious titer loss, is limited.
Developing new methods or formulations in order to stabilize biologically active materials for industrial applications such as vaccines, to improve storage and shipping abilities of these biological materials is thus a continuous goal of the pharmaceutical industry.
One of the proposed solutions has been to maintain the biologically active materials within specific temperature ranges, more particularly at low temperatures, i.e. below 0° C., more particularly until −30° C. and even more preferably until −80° C. This ultra-low temperature storage not only is very expensive, but creates significant inconvenience for storage, transportation and clinic use. It was thus necessary to develop formulations that can be stored at refrigerated condition.
According to one alternative, it has thus been proposed to formulate the biologically active materials with additives of animal or human origin such as albumin, peptone, gelatine or haemaccel. However, the use of such components is limited by safety issues such as risks of allergic reactions or risks of contamination with or transmission of infectious agent (e.g. BSE (Bovine Spongiform Encephalopathy). Additionally, this solution is generally expensive and thus is not compatible with industrial development.
Moreover it is assumed that virus-based material will not maintain its infectivity when stored at refrigerated condition in a liquid form for extended period of time. As a result, there are no reported studies on formulating and storing virus at refrigerated condition in a liquid form. Thus, there remains a need for long-term storage stable formulations of viral preparations.
Another alternative was to preserve the biologically active materials, especially virus-based materials, in a dried form. Among the available techniques of drying biomaterial, freeze-drying (also called lyophilization) represents a key step for manufacturing bio-pharmaceuticals such as vaccines. Freeze-drying leads to dried biological products which are stable at about 4° C. to 8° C. and in some cases until about 25° C. Lyophilization has been used widely to improve the stability of various viral vaccine and recombinant protein products.
Freeze-drying process involves successive steps of freezing solutions or suspensions of biomaterials, followed by primary and secondary drying steps (for a review, see Adams, 2007, Methods Mol. Biol. 368, 15-38). Basically, this technique is based on sublimation of water at subzero temperature under vacuum without the solution melting. However, the rate of water vapor diffusion from the frozen biomaterial is very low and therefore the process is time-consuming. Additionally, both the freezing and drying stages introduce stresses (e.g. concentration of salts, precipitation/crystallization, shear stress, pH extremes, residual moisture remaining through the freeze-drying process, . . . ) that can force the biological material to undergo significant chemical and physical changes and be very damaging to some biological materials such as virus-based materials. It is thus necessary to have adapted formulations allowing preserving the biologically active material during the drying process, and advantageously further during storage/shipping steps.
The prior art provides examples of formulations used for freeze-drying biological materials, more precisely virus-based materials.
In order to limit infectious titer loss of poliovirus preparation, WO89/06542 has proposed to dry the virus stock solution at 37° C. in the presence of a stabilizing solution made up of 10% trehalose as sole protective agent. However, the drop in infectious titer remains large and greater than that observed for the non-dried vaccine.
EP 0 872 249 describes recombinant virus vector preparation comprising a combination of glutamic acid or its sodium salt and glucose.
WO 95/10601 discloses an aqueous recombinant virus solution comprising a saccharide, a high molecular weight structural additive, an amino acid, a buffer and water.
WO 03/053463 discloses vaccinia virus formulations comprising sucrose, dextran, glutamic acid and a buffer which is free of phosphate.
WO 2005/066333 describes a viral composition comprising urea, a sugar, a salt, a buffer, a dispersing agent and a mixture of essential and non-essential amino acids.
WO 2007/056847 discloses a virus-containing formulation comprising sucrose, sorbitol, a polyvinyl pyrrolidone, urea, a TRIS buffer, monosodium glutamate and another amino acid such as arginine, alanine, serine or glycine.
WO2008/114021 and WO2011/121306 describe viral compositions comprising polyethyleneimine compounds, optionally in combination with one or more sugar(s).
Nevertheless, there remains a need for new formulations allowing stabilization of biological materials, and particularly virus-based materials, allowing industrial applications, storage without affecting biological activity of the product, and more particularly to avoid virus titer loss.
The present Invention provides formulation containing virus-based materials, more particularly aqueous formulation, suitable for freeze-drying. According to preferred embodiment, the formulation of the Invention are stable over long-term stability tests as defined hereinafter and more particularly during storage at temperatures above 0° C., particularly between about 4° C. and about 30° C., preferably between about 4° C. and about 25° C., more preferably between about 2° C. and about 8° C., and even more preferably between about 4° C. and about 5° C. (e.g. refrigerated temperature).